1. Field of the Invention
The present invention relates to a semiconductor device having a protection circuit and to an electronic system including the device, and more particularly to a field effect transistor of the insulated gate type having a protection circuit formed on the same semiconductor chip.
2. Description of the Prior Art
Field effect transistors of the insulated gate type designed to deal with large power are generally called "power MOSFETs", and they have associated protection circuits on the same semiconductor chip.
The publication ELECTRONIC DESIGN published on Dec. 5, 1991 introduces in its article of TECHNOLOGY NEWSLETTER a 3-pin power MOSFET device having integrated protective functions against events of short-circuit, over-temperature and over-voltage. According to the article, this power MOSFET device manufactured by Philips Semiconductors in Holland operates based on the associated protection circuit to bring the device into a cutoff state if the junction temperature rises beyond a safe level of about 180.degree. C., and the cutoff state is retained by a latch circuit included in the over-temperature and short-circuit protection circuit until the control input is brought to a low level.
Another publication TECHNICAL PUBLICATION PRODUCT INFORMATION SCO12 published by Philips Semiconductors introduces in its article entitled "TOPFET: a new concept in protected MOSFET", pp. 1-4, a brief internal block diagram of a 3-pin MOSFET having integrated protective functions against events of short-circuit, over-temperature and over-voltage. The article reports that when the overload protection circuit operates (due to over-temperature or short-circuit), the power MOSFET of the output stage has its gate signal latched to a low voltage level so that it is kept cutoff, and this protection state remains so far as the input voltage is above a latch reset threshold of 3.5 to 4.5 volts.